The method herein relates to implanting an embryo transplant from a donor mammal into the uterus of a recipient mammal.
More particularly, the method herein relates to a method for implanting an embryo transplant from a donor mammal into the uterus of a recipient mammal by surgical techniques for limiting damage to the reproductive tract and other body tissues of the recipient mammal generally incurred by present surgical techniques and inhibiting the likelihood of abortion of the implanted embryo from the uterus.
Current methods of implanting embryos into host animals during the estrus cycle for such host animal to carry the embryo through the normal gestation period include using surgical and nonsurgical techniques. For example, nonsurgical techniques of implanting embryos into host animals are performed by inserting a catheter through the vagina and into the uterus of the animal. The catheter serves as a conduit through which the embryo is transferred into the uterus. The catheter is inserted through the vagina, through the cervix and into the uterus. Once the catheter is past the cervix, it is manipulated by the end extending from the vagina to extend the catherter into a uterine horn of the uterus. The uterine horn in which the catheter is placed leads to an ovary on which a corpus luteum is formed. Such a nonsurgical technique is undesirable. The passing of the catheter through the cervix can damage the cervix. Additionally, the cervix can be damaged when the catheter is being manipulated to position the catheter into the proper uterine horn. The endometrium of a mammal is also easily damaged during post-estrus as the tissue comprising the cervix and endometrium is readily subject to hemorrhage. It is desirable to prevent physical damage to the cervix and endometrium as the condition of the cervix and endometrium is integral to inhibiting abortion of an embryo during gestation.
Current surgical techniques for implanting embryos into the uterus of recipient mammals generally comprise anesthetizing the animal and performing ventral abdominal or lumbar regional surgery on the animal to locate the uterine horn in which to implant the embryo. Such surgery requires the making of an incision through the walls of body tissue and generally requires total anesthetizing of the animal. This procedure is undesirable in the bovine species as they do not tolerate such total anesthetization and can die from the anesthesia. The procedure is also expensive, time consuming and is difficult to perform other than in an equipped operating room. Additionally, there is a possibility of infection to the recipient mammal as the peritoneal cavity is opened. Also, with such surgery, there occurs postoperative adhesions on the incised tissue which makes multiple transplants to the same recipient mammal difficult and sometimes ineffective in producing a sustainable gestation period. Such adhesions do not have the elasticity of normal tissue. The adhesions form after each surgical operation. With the build up of adhesions, it is generally recommended that each recipient animal function as recipient for only a few transplants in order to maintain viability of the embryo throughout the gestation period. It is desirable to provide a method of implanting embryos that would reduce the difficulties and drawbacks of the current surgical methods and would improve the likelihood of the recipient mammal retaining the embryo through a normal gestation period.